Safety switch plug



June 4, 1929.

J. GOERGL 1,716,041

SAFETY SWITCH PLUG Original Filed July 30, 1926 IIIIIIII INVENTORATTORNEYS '25 peratures.

plug, looking along thelinc 44' Patented June 4,1929.

UNITED STATES v PATENT OFFICE.

eomi' sonnet, or cnrcAGa-nnmom, ASSIGNOR or ommnr ro a. m. nvm, or

CHICAGO,

ILLINOIS.

SAFETY SWITCH PLUG.

Application filed July 80, 1926, Serial No. 125,997/ Renewed August 31,1928.

My invention relates to improvements in safety switch plugs, and itconsists in the combinations, constructions, and arrangements hereindescribed and claimed.

An objectof my invention is to provide a plug which may be used inconnection with electric irons or other appliances of the type, andwhich contains switching mechanism by means of which the current may becut oil? or turned on at a predetermined temperature.

A further object of my invention is to provide a device of the typedescribed in which the temperature at which the current is automaticallycut off or turned on maybe varied so that in the case of an electriciron the heat may be regulated as desired and automatically maintainedat a substantially given temperature.

' A further object of my invention is to pro-' vide a plug, containing athermostatic element whichautomatically moves to cut off or turn on thecurrent with means for controlling the movement of the thermostaticelement, so that-it will operate at difierent tem- A further object isto provide a plug having the size of the ordinary plug, and which may beused with the ordinary electric iron or other electrical device thatmakes use of plugs. a

Other objects and advantages will-appear in the following specification,and the novel features of the invention will be particularly pointed outin the appended claims. 7 My invention is illustrated in the accom'panying drawings, forming part of this ap plication, in which F Figure1 is a side view of a plug, constructed according to my invention, j. VFigure.2 is aface view of one side of the plug, i s. Figure 3 is aseetlonal v ew along the line 33 of Figure 2,

Figure 4 is a face view of one half of the of Figure 1 in the directionof the arrows, Figure 5 is an enlarged sectional" view -,showing thethermostatic element and the- 4 spring for controlling the same.

Figure 6 is an enlarged sectional view through a portion of the springcontacts, 1

plan view of the spring conviews of opening being of such size as toreceive the ad-; justing knob later to be described; this enables thepart B which serves as a cover to be removed and replaced withoutinterfering with the internal parts; As will be observed from FignreB,the section A is recessed to provide for a condenser 10, Whose oppositeends have connected therewith conducting pins 11 and 12, respectively.The portion B is also recessed, and between the portions A and Bare thethree conducting-plates 13, 14

' and 15, shown in Figures 9, 10and 11. vThe plate 13 lies next to thewall of the portion vB, (see Figures 3 and 5). This plate has one cornerbent up to form a hOOkr 13, by means of which one of the sets of springcontacts is secured. The form .of these spring contacts is shown inFigures 6 and 7; It will material, and which are held to-, y means ofscrew bolts 9. The secbe observed that thereis a strip 16 which has asemi-circular portion 16 stamped thereon vand that to this strip isanother strip 17, hav-,

ing a spring portion '17 bent in the manner shown in Figure 6, so thatwhen a conducting terminal pin enters from the bottom, the spring 17will be moved aside and will form a close contact with the pin, whichispressed. upon the conducting side 16. As will be seen from Figure 3,this spring contact is secured to the up-turn'ed' pogtion 13 by means ofascrew. The lower en of the contact 16' fits'intoarecess in theassembled plug sections and is, therefore, held securely;

Referring now again to Figures 3, 5 and 8, it will be seen-that theplates 13, 14 and 15 are separated by suitable insulation. The

central plate'l has a conducting terminal 18, whiclf extends through anopening 19 in the plate 13; the latter is provided with a thermostaticrod or arm Q0, which 'is' made of "metal and which, when heated, tendsto spring. away from the terminal 18 and when cooled tendsto contactwith it. This strip maybe of any suitable material, such as acompound-metal strip, and it is pressed upon inormally by/a spring 21,which is secured at- 22-to the plate 13. The upperend of the Spring isarranged to be engaged by the end of a screw 23, whiclr is carried by amilled insulating knob 24. The latter is pressed on subsequent operationof. the

pass through the conducting by a spring 25, which tends to push the headoutwardly thus exerting 'friction on the threads of the screw so as tohold'the latter in adjusted position. In Figure 5 the ther mostaticelement 20 is shown away from the terminal. When the spring 21 is forcedby the screw23 toward the thermostatic element,

it will require a greater amount of heat for the latter to leave theterminal. 23 engages with a threaded aperture in a bridge 13, the endsof which are secured by screws 13, to the plate 13.; a'boss 13 on thebridge surrounds the'threaded aperture and serves to center'and hold thespring 25. The

outer end of the spring is held beneath the skirt 24 at the margin ofthe knob 24. e

The three plates 13, 14 and 15, as stated, are insulatedfrom each otherand are held in spaced relation by means of screws 26, which plates, butdo not electrically connect them, as shown in Figure8.

:A spring socket contact 16*, similar to the spring contact 16 issecured to plate 15 in substantial alignment with the contact 16.

The condenser is connected with the plate 14 on one side and the plate13 on the other. From the foregoing description of the vari ous parts ofthe device, the operation thereof may be readily understood. When theparts are assembled, the plates 15 and l are connected to the' wiresleading from the source of current. As has been stated, the'sock ets,WhlCh receive the terminal pins of the electrical device such aselectric iron, are carried by the plates "15 and 13 respectively.Normally, the thermostatic element 20 is in engagement with theterminal18, thereby closing1 the circuit through the plates 13 and 1 anWhen, now, theithermostati element reaches a certain temperatu're,-i wll move away from the terminal 18, and

this will cause the breaking-of the circuit. In order to condenser 10,

prevent arcing, I provide the which will permit the break to be madewithout. arcing and destroying the contacts; When itis desired to makethe automatic" circuit opener operate at a higher I temperature, thenthe milled thumb knob 24 is turned to the 'right,forcing the spring 21againstfthe thermostatic arm, so that'in the device greater The screw,

hence closing the circuit through the elece t tric'al device.

force must be; exerted by the thermostatic arm to move away from thecontact 18. In

other words, the arm which is reinforced by the spring may be made tooperate at yarious desired temperatures.

It will thus be seen that my improved plug not only embodies anautomatic switch'for. operating at a predetermined temperature, but italso provides for the regulation of the temperature, or the adjustmentto various temperatures so as to give more or less heat where, an ironis being used.-

I claim:

1. A switch p lug, comprising a pair of insulating sections, one of saidsections having a boss provided with an opening, a stationary co tactcarriedflwithin said plug, a thermo-- statically actuated arm hav ng oneend nor-4 mally in engagement with said adapted to move away from saidcontact, at a predetermined temperature, a spring for opposing saidmovement, a screw in engagement with said spring, surrounding the headerthe screw and secured thereto for voperating the screw, said receivablein the opening in said spring for exerting pressureon for frictionallymaintaining the screw in its adjusted position.

3: A switch plug, tion, a pair of insulating sections, one of, saidsections having a. lateral opening, a station ary contact carried withinthe said thermostatically actuated arm having one end normally inengagementwith said tact andadapted to move away from said con- 115 -f"oppos ng said movement, a bridge overly-I act at a pre-determinedtemperature, a spring P ug a contact and- 7 an insulating knobmaintainthe screw in its adjusted ob sun comprising incombina gsaidcontact, a screw engaging said bridge, 7

f'and. adapted to contact said spring, a knob;.-,

'for actuating said screw, and means for maintaining saidknob and screwin'adjusted posi-' tions, the openingthroughsaid section being of a-size to permit said knob to pass. therethroughi 4 A plug comprising,

;section having an. opening, a stationary cons in combination, an mainsection and a eover section, saidcover tact, a movablecontact, saidmovable contact being in theform of a 'bimetal arm, said contacts beingnormally in engagement and said movable contact being adapted to moveaway from said stationary contact at a predetermined temperature, aspring for opposi-ng said movement, a bridge overlying said contacts, ascrew engaging said bridge and contacting said spring, a knob foractuating said screw, all of said parts being fixed to said mainsection, said cover section overt;

ing said parts, and the opening therein serving to accommodate saidadjusting screw whereby said cover section may be removed withoutinterfering with the operatin parts,

- JOHN GOEL GL,

